Well I certainly don't wish to step on anyone's toes here but is it possible that Google does not index your site on purpose ? I've heard that they can block sites based on their own discretion. Is there a way to find out from Google themselves if you're not being indexed on purpose or if they get errors from your site so they don't index it? Not saying this is the cause, just curious if it's possible to find out for sure directly from Google.
